The present invention relates to a method and device to determine a relative reference position for an angle measurement of an object and more particularly to a method and device to determine a relative reference position for an angle measurement of an object of any shape.
In the determination of angle position of measurements, marks or other properties of a test or other object, it is necessary to make such measurements with respect to a reference point or reference angle. For instance, in the measurement of rotor imbalances, the imbalance is measured in terms of size and angle position so that additional weight can be added to the rotor at the correct points to counteract the imbalance.
Under conventional systems, a mark is made on the test object or rotor in order to obtain a reference angle signal, and the impulse generated thereby is used as a reference for the angle measurement. It is also known (for instance from German Pat. Application Ser. No. 2 243 002) that, with rotors which are manufactured with imbalance counteraction points at specified positions, such as with electric motor anchors, the counteraction points on the rotor are scanned and the impulses gained hereby are used as a phase reference signal impulse. With this method it is also necessary to subdivide the round angle represented by the rotor diameter into several incremental angles in order to make precise imbalance counteraction. With conventional processes, this round angle division results from the impulses arising from the individual counterpoints during the rotor rotation.